Université de Liège
TDEE & ACE, Institut Montefiore
Sart Tilman, Quartier POLYTECH, allée de la Découverte 10, 4000 Liège
Environment: EMF & Contact current hypothesis (1999-2013)
C. Geuzaine, JL. Lilien (*), PP. Barbier, V. Beauvois, P. Dular, R. Sabariego
The research project focused on the origin of contact currents in Belgian residential housing. The measurement campaign was completed, with a total of about 150 houses measured. No correlation was found between contact currents and the ambient magnetic field produced by electrical power lines. Instead, the contact currents in Belgian houses were shown to predominantly originate from leakage capacitive currents in domestic wiring. This new finding is at odds with similar studies performed in the USA, but was confirmed theoretically (using computer simulations) and experimentally (via measurements). It was shown that the difference between the Belgian and US situations is probably mainly due to the different earthing systems used in the two countries, the TN-scheme used in the USA being more sensitive to ambient magnetic fields than the TT-scheme used in Belgium.
JL. Lilien, C. Geuzaine, V. Beauvois, P. Dular, R. Vázquez Sabariego, P.P. Barbier
A large campaign of measurement on 150 Belgian houses has been performed during the project.
If internal electric field is indeed the parameter to consider for biological concerns into human body, contact current is the main potential source of high internal electric fields. The effect from fields generated by power lines in that regard is much smaller.
The contact current originates from capacitive current leakage for typical domestic cables. It is thus recommended to use domestic cable with metallic drain to avoid these leaks. Coupled with appropriate earthing, that would certainly eliminate that potential source of concern for human beings.
JL. Lilien, C. Geuzaine, V. Beauvois, P. Dular, R. Vázquez Sabariego, P.P. Barbier
We have developed and implemented computational tools to study and understand the influence (on contact currents) of leakage currents (from electrical cables) near water pipes. We have noticed that the leakage capacitive currents of electrical cables influence and could justify the contact current level in houses.
Concerning the contact current measuring campaign, we have increased the number of measurements. The number of hypersensitive people’s houses has increased up to 15% of total sample and the contact current level is around 8 µA.
We also evaluated the impedance of the human body to contact current. Thanks to this study we can better justify the use of the 1kΩ resistor used in the campaign .
We also collaborate with other BBEMG teams to simulate cells submitted to an E field in a Petri box.
Regarding the comparison of two pilot houses (a passive house and a so-called hypersensitive house), the first step has been completed and shown that the contact current level in passive house using VXVB cable (with ferrite) is extremely low. In parallel with the measurement campaign we have started the development of a computer program to accurately compute the capacitive coupling between the various conductors in these houses.
Contact current, sensitivity to electricity & 50Hz electric and magnetic fields
JL. Lilien, C. Geuzaine, V. Beauvois, P. Dular, R. Vázquez Sabariego, P.P. Barbier & R. Lorphèvre
Our main objective is to quantify and qualify the contact currents, both by simulations and on-site measurements.
Our team has developed specific numerical tools to compute and understand the influence of High Voltage (HV) power lines around 3D electrical structures in private homes . We can detect critical configurations that produce high or low contact currents in an isolated house or in a network of houses. The type of network scheme (TT, TN) and the geometry of the connections are as important as the intensity and the direction of the magnetic induction field.
On-site measurements (about 100 houses) were performed to understand the level and the origin of these contact currents in the Belgian housing stock. Instead of a random sample, we preferred to measure (in a strict protocol and quite prepared) these contact currents for residences located near the lines, in order to obtain a statistical base to assess the potential correlation between the ambient magnetic field and current contact. It should be noted that very often, the contact current level is near the electrical noise that was in the house. The apparatus used has been chosen accordingly. Many investigations have been performed to understand the origin of these contact current and preventive means have been investigated, both by measurement, model and simulations.
Another important aspect of our research is to inform people about our research and to compare the potential biological effects (by an internationally recognized indicator) between contact currents and exposure to electric and magnetic field.
We also performed a comparison of 15 studies about the human body interactions with E-field, B-field and contact currents. They allow us to classify the influence of these sources. Contact current is clearly a dominant factor.
We also made a device for injecting a current (1 mA max) in a forearm of a person. This device allows you to test the sensitivity of the people at different frequencies and shapes obviously including the 50 Hz, with different protocols. Indeed, the literature (Leitgeb, 2008) has shown a correlation between sensitivity to electricity and hypersensitive peoples. This removable device could help test for tests on site.
JL. Lilien & B. Mattivi
The first aim is to obtain better knowledge of the electric and magnetic fields environment (local and ambient sources) and to pass on valid scientific information to the public domain.
It is necessary to keep in contact ,on a scientific level, with people who are afraid of ambient ELF. They are generally very satisfied by any help (such as local measurements and discussions) provided by independent scientific people. That is one of BBEMG aims which should still be continued.
It is a fact that higher fields than those induced by overhead lines may be found in some industrial locations, independently of any OHL in the vicinity. Most of them may easily be reduced if the problem were taken into account at the design stage.
Some new trends of possible explanations of increased risks of childhood leukaemia shown by epidemiologic studies were investigated and are promising.
This new hypothesis is based on contact current. The connection with childhood leukaemia needs to be more deeply studied. It is the first aim of our research project. The major impact is that such trends may lead to an easy solution based only on electrical installation recommendations.
A second goal concerns hypersensitive people. We feel that the current level of perception may help to objectify the detection of hypersensitive people who may then be tested on some biological parameters and thus help to find appropriate bio-markers. This might help develop appropriate therapies.
The perception level, as detailed in the literature, is an important feature and to have our own data base would be of major importance to better understand the impact of some parameters (such as frequency, signal shape, duration, impedance of the human body, etc.).
A first “draft” system for testing human beings at different levels of current and different frequencies (from about 40 Hz to about 1 kHz) was implemented and used for the first evaluation. The first results seem convincing.
C. Geuzaine, V. Beauvois, P. Dular, R. Vázquez Sabariego & R. Lorphèvre
The Unit of Applied Electricity acts as a technical, logistical and didactic support to all biomedical teams. Therefore, our main activities are consultancy & support for all stakeholders, advice on the purchase of instruments measurements, design and development of special devices in accordance with the requirements of the users, specific literature review, etc.
Our team also develops numerical tools (as GetDP), specifically for calculating magnetic and electric fields around 3D electrical structures.
W. Legros, P. Pirotte & JL. Lilien
Our aim is to obtain a better knowledge of environmental electric and magnetic fields (local sources, ambient). Many residential and occupational magnetic induction field measurements were performed in order to have a better knowledge of exposure to magnetic induction fields.
Residential measurements are related to the houses of people who either live near overhead high voltage power lines or are considering the purchase of a development site under an overhead power line. Measurements were also made in the study conducted by the Psychoneuroendocrinology Unit (M. Crasson and J.J. Legros). Magnetic field measurements were taken in 95 homes, specifically in each room occupied for at least one hour per day, to provide an estimate of total-time-integrated exposure. Magnetic fields were recorded at three different places in each room, near electrical appliances, and near the energy meter. The examiner noted all particular characteristics of the house.
Lilien, J.L., Dular, P., Sabariego, R.V., Beauvois, V., Barbier, P.P., & Lorphevre, R. (2009).
Effects of extremely low frequency electromagnétic fields (ELF) on human beings.
In Proceedings of International colloquium – Power Frequency Electromagnetic Fields ELF EMF, June 3-4, 2009, Sarajevo, Bosnia-Herzegovina.
Lilien, J.L., Dular, P., Sabariego, R.V., Beauvois, V., Barbier, P.P., & Lorphevre, R. (2008).
Effects of extremely low frequency electromagnétic fields (ELF) on human beings. An Engineer point of view.
Revue E tijdschrift – 124ste jaargang/124ème année – n°3-2008.
Mattivi, B., Beauvois, V., Dular, P., Lilien, JL., Lorphèvre, R., & Sabariego, R.V. (2006).
Hypersensitivity to Electricity: The effect of the current waveform on the perception level.
4th Int Workshop on biological effects of electromagnetic fields. Crete, Greece, Oct 2006.
Hoeffelman, J., Decat, G., & Lilien, JL. (2004).
Assessment of the Electric and Magnetic field levels in the vicinity of the HV overhead power lines in Belgium.
CIGRE, 2004, CIGRE session papers, Group C3 (8 pages).
Crasson, M., Legros, J.J., Scarpa, P., and Legros, W. (1999).
50 Hz magnetic field exposure-influence on human performance and psychophysiological parameters. Two double-blind experimental studies.
Bioelectromagnetics, 20 (8), p. 474-486.
A summary of standards for human exposure to electric and magnetic fields at power frequencies.
Working Group 36/01 and 06.CIGRE (Joint paper). Electra 1998, August, 179, 51 p.